3D scanners are widely known from the art, and so are intraoral dental 3D scanners (e.g., Sirona Cerec, Cadent Itero, 3Shape TRIOS).
The ability to record surface color is useful in many applications. For example in dentistry, the user can differentiate types of tissue or detect existing restorations. For example in materials inspection, the user can detect surface abnormalities such as crystallization defects or discoloring. None of the above is generally possible from surface geometry information alone.
WO2010145669 mentions the possibility of recording color. In particular, several sequential images, each taken for an illumination in a different color—typically blue, green, and red—are combined to form a synthetic color image. This approach hence requires means to change light source color, such as color filters. Furthermore, in handheld use, the scanner will move relative to the scanned object during the illumination sequence, reducing the quality of the synthetic color image.
Also U.S. Pat. No. 7,698,068 and U.S. Pat. No. 8,102,538 (Cadent Inc.) describe an intraoral scanner that records both geometry data and texture data with one or more image sensor(s). However, there is a slight delay between the color and the geometry recording, respectively. U.S. Pat. No. 7,698,068 requires sequential illumination in different colors to form a synthetic image, while U.S. Pat. No. 8,102,538 mentions white light as a possibility, however from a second illumination source or recorded by a second image sensor, the first set being used for recording the geometry.
WO2012083967 discloses a scanner for recording geometry data and texture data with two separate cameras. While the first camera has a relatively shallow depth of field as to provide focus scanning based on multiple images, the second camera has a relatively large depth of field as to provide color texture information from a single image.
Color-recording scanning confocal microscopes are also known from the prior art (e.g., Keyence VK9700; see also JP2004029373). A white light illumination system along with a color image sensor is used for recording 2D texture, while a laser beam forms a dot that is scanned, i.e., moved over the surface and recorded by a photomultiplier, providing the geometry data from many depth measurements, one for each position of the dot. The principle of a moving dot requires the measured object not to move relative to the microscope during measurement, and hence is not suitable for handheld use.